Generally, the computer casing has a machine frame for installing a disk drive, for example, an optical disk drive or a floppy disk drive. The disk drive is locked to the machine frame. However, it has the problem for locking a disk drive to the machine frame, that is, it is inconvenient to lock or unlock the disk drive.
In one improvement, with reference to FIGS. 7 and 8, the frame of sliding track 5 includes a body 51 and a hook 52. A conductive pin 511 and a hole 512 are formed on a bottom of the body 51. One end of the body 51 has a plurality of blocks 513 having cambered surface. When pressing the hook 52 into the body 51, the hook 52 can be buckled to be below the blocks 513. A conductive hooking unit 521 of the hook 52 dose not protrude out of the hole 512 of the body 51. The conductive pin 511 of the body 51 of the sliding track 5 and the conductive hooking unit 521 of the hook 52 are embedded into the pin holes of a disk drive (not shown). In above structure, since the hook 52 presses upon the body 51, and is confined by the blocks 513. Meanwhile, the conductive hooking unit 521 of the hook 52 protrudes out of the hole 512 of the body 51 to be buckled to the disk drive. Since the positioning of the hook 52 and body 51 is not preferred, when pulling the front end of the hook 52 to drive the disk drive, the hook 52 is loosened from the body 51 so that the conductive pin 511 and the conductive hooking unit 521 break. Thereby, the guide track is easily destroyed. Moreover, it is often that the gaps between the disk drive and the machine frame are too larger or too small so that the assembly is too loose or even they cannot be assembled.